Cracking with zeolite catalysts promoted with uranium or uranium plus silver

Abstract

Uranium oxide or uranium and silver oxides in combination with hydrogen or rare earth oxides are exchanged into zeolites as components of zeolite cracking catalysts to increase the olefin content of the gasoline and, thus, enhance the yield of high octane components as well as reduce the coking tendency of the catalyst.

What is claimed is: 
     
       1. A method of catalytically converting hydrocarbons to produce gasoline of increased aromatic content which comprises contacting a hydrocarbon feedstock in the absence of added hydrogen at a temperature of 800° to 1000° F. with a catalyst consisting essentially of 5 to 50 percent by weight of a crystalline zeolite having a silica to alumina ratio of 2.5 to 6, dispersed in an inorganic matrix in which from 5 to 15 percent urania, silver or mixtures thereof are incorporated into the zeolite by ion exchange. 
     
     
       2. The process according to claim 1 wherein the crystalline zeolite is in the hydrogen form prior to exchange with a silver, uranium or mixed silver and uranium salt solutions. 
     
     
       3. The process according to claim 1 wherein the crystalline zeolite is in the rare earth form prior to exchange with the uranium or silver or mixed uranium and silver salt solutions. 
     
     
       4. The process according to claim 1 wherein the feedstock is a gas oil boiling in the range of 400° to 1000° F. 
     
     
       5. The process according to claim 1 wherein said inorganic matrix is a mixture of silica-alumina and clay.